Marie Colvin's mother Rosemarie at the funeral in Oyster Bay, Long Island. Three hundred people attended the service. Photograph: Shannon Stapleton/Reuters

Marie Colvin, the Sunday Times war correspondent whose reputation for covering difficult stories in the world's most dangerous places made her one of the leading reporters of her generation, was laid to rest in her home town near New York on Monday, almost three weeks after she was killed on assignment in Syria.

Colvin's family followed her coffin into their local church in Oyster Bay on the north shore of Long Island, while a lone piper played Amazing Grace. Sunday Times proprietor Rupert Murdoch and editor John Witherow joined immigrants who followed her dispatches from their troubled home countries for an intimate ceremony.

Among the 300 or so mourners, there was still a sense of incredulity that having survived so many close shaves during a long and illustrious career, Colvin was killed trying to escape the shelling of a house used by journalists covering the bombardment of Homs.

Reporters who had shared tough times under fire joined supporters of the anti-repression movements she championed to pay tribute to Colvin, who was 56. Among the mourners were the BBC's Jeremy Bowen, the Sunday Times foreign editor Sean Ryan, and the former assistant secretary of state James Rubin, husband of Colvin's close friend and television journalist Christiane Amanpour, who was in London and unable to attend.

Katrina Heron, Colvin's best friend from college at Yale, delivered the eulogy at St Dominic's Roman Catholic church, near her childhood home and school. Heron recalled her strong sense of humour and love of a party. "She would probably say this was a bit sedate for her tastes. I think she'd take one look around and say 'Can we move this party? I know a great little place down the road'," Heron joked, to affectionate laughter among the mourners.

Colvin would come back to the US between covering conflicts to "have fun" and gather her friends with her knack of bringing people together, Heron said. "Marie lived her wish to know that there was tenderness in the world. She lived it fully and she died for it. We are so proud of her."

Her brother Michael wiped his eyes and hugged their mother Rosemarie as she gazed at bouquets of lilies and white carnations laid next to Colvin's simple coffin.

Sean Ryan led a prayer, saying that Colvin spoke for the innocent and those who suffer and needed mercy.

Leading the service, guest pastor Dennis Mason, a cousin of Colvin, hailed her work for giving "a voice to the voiceless". He said: "You risked yourself so many times over for those to whom no-one else would show mercy."

He went on: "Her first thought was never herself. She was the most respected, talented, compassionate, selfless journalist of her generation."

The quiet and low-key ceremony served as a contrast to the violent scenes witnessed by Colvin. "She was appalled by war, appalled by what it did to children and the innocent bystanders that made up the population," Heron said in her address.

Colvin's close British friend Jane Wellesley gave a reading from the book of Thomas. "The time has come for me to be gone. I have fought the good fight to the end, I have run the race to the finish," she read.

As Colvin's coffin was taken for a private cremation, a piper played the lament Going Home.

Bowen, who had flown in from Dubai for the funeral, having shared many war assignments with Colvin, said he had received an email from Colvin the night before she was killed in Syria.

"She said that going to the dark corners of the world was the justification for the kind of work we do," he said.

Amid the violence in Syria, it was a challenge to get Colvin's body out of the country. A Polish diplomat received her remains from the Syrian Red Crescent, before flying them home to New York via Paris.

Only a few hours before she died, Colvin appeared in a final live broadcast with CNN's Anderson Cooper, telling him the Syrians were shelling "a city of cold, starving civilians."

"It's a complete and utter lie that they are only going after terrorists," she added. "There are no military targets here."

Outside the church, Syrian-American musician Malek Jandli and several fellow supporters of Syria's oppostion movement held banned rebel flags and said they had come from Atlanta, Georgia, to honour Colvin.

"She was killed in Homs just steps from where I grew up. She was exposing the terrible crimes of the Assad regime and she had more courage than me," Jandli said.

Across the street from the church, a group called Tamils in America held large pictures of Colvin, with the distinctive patch covering the eye she lost when reporting on the civil war in Sri Lanka, and printed with the words: "Uncrowned queen of intrepid journalists. You will never be forgotten."